As I have recieved several requests for the pieced together, converted midi files, I've decided to share the wealth and post these files on my website:
http://stephen1297.googlepages.com/latracks
There's links to X-Wing, Tie Fighter and Dark Forces midis ripped straight from the game. The normally fragmented in-flight midi files in XW & TF have been pieced together so that all of the songs are whole.
Enjoy!